Pushkin compiler: canonical JSON Schema 2020-12 → strict four-target bindings (TS/Zod, Pydantic v2, Rust serde, SQL DDL), each stamped with a schema-epoch header (spec §5.2).
Crate contract: emission is deterministic (same input → byte-identical
output) and total over the constrained authorable subset; anything
outside the subset is a loud Unrepresentable rejection with named
alternatives — never a silent drop (spec §5.1).